I talked to the dealer this week and they said they've been hearing this from multiple people. However, I think I may have figured out a way to get the settings to stick in my truck. I went into settings > apps > audio > and changed the equalizer in there. That made the settings stick for me and haven't cleared over the past 3 days. Hopefully this may work for you as well!
Hey everyone, new to the forum here. I just bought at 2021 last week and I'm having the same issue. I contacted Chevy directly and the advisor told me that they "couldn't find anything in the owner's manual about saving this setting" lol. That's about all the further I could get with the advisor before they told me to work with my local dealership. I'm going to call sometime this week.